Field of the Invention
The invention relates to a portal incorporating an RFID tag reader for notification of the passage of an RFID tag through the portal, and a 3-D visual recognition system for identifying an object to which the RFID tag is attached.
Description of the Related Art
Portal readers are utilized at portals, such as open passageways, man doors, hallways, garage doors, stockyard gates, and the like, to monitor the passage of objects having RFID tags through the portal, and record information transmitted to the portal reader from the RFID tags. The information provided by an RFID tag can include data concerning the object to which the RFID tag is attached.
A portal reader detects the presence of a signal from an RFID tag. However, a portal reader does not “see” the tag from which it is receiving the signal, nor can it differentiate between objects to which RFID tags are attached. A problem frequently encountered with portal readers is the tendency to record information from RFID tags that have not actually passed through the portal. For example, an object with an attached RFID tag may pass a portal reader within the range of the RFID tag without passing through the portal, i.e. passing along and parallel to the portal. These are frequently referred to as “stray reads.”
Photo-eye sensors can be mounted at an appropriate location relative to the portal in order to trigger a portal reader when the object encounters the sensor line-of-sight and passes through the portal. Analytical techniques or algorithms can be utilized to estimate the direction of travel and speed of a tag from the signal sent by the tag. Data analysis can be performed utilizing received signal strength indication (RSSI), phase analysis, or Doppler analysis.
Such techniques suffer from an inability to provide more than an estimate of whether a tag has passed through a portal or not. Thus, there is a need for a system providing both information from an RFID tag and verification that the tag has passed through the portal.